Floatable vessel



R. H. WILLIAMSON FLOATABLE vnssm, V

3 Sheets-Sheet '1' ,Eged Feb. 28, 1968 Oc't- 1959 g R. H. WILLIAMSON3,47

FLOA'I'ABLE VESSEL Filed Feb. 28, 1968 3 Sheets-Sheet 2 United StatesPatent US. Cl. 114-5 4 Claims ABSTRACT OF THE DISCLOSURE The inventionis concerned with a floatable vessel consisting of an upright columncarrying a ballast chamber positioned adjacent the lower end of thecolumn, a buoyant superstructure slidably mounted on the column formovement between a lower position adjacent the ballast chamber and anupper position adjacent the upper end of the column and means forsecuring the superstructure in the upper position. The inventionprovides a mooring arrangement consisting of a plurality of mooringlines connected to the vessel adjacent the lower end of the column andbeing arranged for attachment to anchorage points, the lines eachextending over a support associated with the superstructure such thatdisplacement of the latter along the column away from its lower endassists in tensioning the lines.

This invention relates to certain improvements in the floatable vesselforming the subject of co-pending patent application No. 569,617, nowUS. Patent No. 3,408,821, granted Nov. 5, 1968.

In the specification of the above application there is disclosed afloatable vessel including an upright column which carries a ballastchamber positioned at or near the lower end of the column, a buoyantsuperstructure which is slidably mounted On the column for movementbetween a lower position adjacent to the ballast chamber and an upperposition at or near the upper end of the column and means for securingthe superstructure in the upper position. Such a vessel will be referredto hereafter as a Floatable vessel as defined.

When considering the tensioning of say four mooring lines of a vessel,the mooring lines should be initially taut if a satisfactory mooring ofthe vessel is to be achieved. If the vessel is moored by first attachingtwo of the lines to the vessel and then bringing the third and fourthlines and the vessel together, the third and fourth lines require to betensioned against their anchors and the vessel against the other twolines and their respective anchors which entails considerabledifficulty.

According to the present invention, there is provided floatable vesselas defined, wherein the vessel is provided with a plurality of mooringlines connected to the vessel at or near the lower end of the column andbeing arranged for attachment to anchorage points, said lines eachextending over a support associated with the superstructure, wherebydisplacement of the superstructure along the column away from its lowerend assists in tensioning the lines.

In order that the invention may be fully understood, one embodimentthereof will now be described, by way of example, with reference to theaccompanying drawings, in which:

FIGURE 1 illustrates the vessel described in the above mentioned patentin the operational condition and provided with the mooring lines inaccordance with the present invention attached to anchorage points,

FIGURE 2 illustrates a plan view of the vessel with the superstructureremoved,

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FIGURE 3 illustrates a detail of the vessel shown in FIGURES 1 and 2,

FIGURE 4 illustrates a modification of the detail shown in FIGURE 3, and

FIGURES 5 to 8 illustrate the vessel at various stages in beingconverted from a towing condition to the operational condition beforethe latter condition is reached.

Referring to the drawings, the vessel itself is of the constructiondescribed with reference to the FIGURES 1 and 2 of the drawingaccompanying the above mentioned patent and will not be described indetail herein. Broadly the vessel is composed of a column 1 providedwith a ballast chamber 2 and carrying a buoyant superstructure 3. Thevessel is provided with four mooring lines 4 each composed of a rope(not shown) and a chain cable 5 by means of which the rope is attachedto the vessel. Each cable passes over a sprocket 6, and extends to afixing point 7. Each sprocket '6 is mounted on a mooring ring 8 by meansof a bracket '9, the sprocket itself being rotatable on a pin 11 (FIG.3). The mooring ring encircles the column 1 and is connected to thesuperstructure 3 by two lifting cables 12.

To accommodate the brackets 9, sprockets 6 and cables 5 when thesuperstructure is positioned at the lower end of the column immediatelyabove the ballast chamber 2, the latter is provided with four recesses13 merging respectively with four further recesses 14.

In the towing condition of the vessel shown in FIG- URE 5, all fourcables 5 are stowed in their respective recesses 13 in the ballastchamber 2. If the previously mentioned mooring ropes are already at thesite attached to anchorage points on the sea bed, the ropes will beconnected to the cables 5 on arrival at the site. It will be seen fromFIGURE 5 that all the mooring lines at this stage are slack.

The reminder of the mooring procedure is as follows. The ballast chamberis first partly flooded and is allowed to sink to a position where thelifting cables 12 are fully extended to support the mooring ring 8(FIGURE 6) and is further flooded slightly to cause the superstructure 3to engage correctly with an associated collar 15 as described in theabove mentioned patent, when the superstructure is locked to the collar(FIGURE 7).

Now the 'ballast chamber is flooded completely and allowed to sink to adepth where the superstructure reaches its operational position at thetop of the column (FIGURE 8). This causes the mooring ring to be liftedup the column to a position approximately half way up the column whereatthe ring is locked to the column and so also is the collar 15 locked tothe column 1 as described in the above patent. At this stage the slackis taken out of the cable chains 5.

Finally the ballast chamber is unballasted slightly to allow the vesselto rise to the operating position (FIG- URE 1), this final upwardmovement applying a tension to the mooring lines 4.

If it is desired later to inspect the mooring attachments, the aboveprocedure may be reversed.

The locking of the mooring ring to the central column is arranged sothat should buoyancy in the column and ballast chamber be lost, thecolumn can release from the ring in a similar manner to the arrangementfor detaching the superstructure from the column as outlined in theabove mentioned US. patent.

It will be seen that the above arrangement greatly facilitates themooring of the vessel in that the securing of the mooring ropes to thecables can be carried out under slack mooring line conditions. Thearrangement of the double purchase of the chains over approximately halfthe length of the vessel enables the mooring lines to be tensioned as adirect result of the conversion of the vessel from the towing to theoperating condition.

The chain cables 5 may if desired be replaced by studlink cables 25 inwhich case the sprocket 6 would be replaced by toothed wheels 26, thisbeing illustrated in FIGURE 4.

I claim:

1. A floatable waterborne vessel including an upright column carrying aballast chamber adjacent its lower end and a buoyant superstructuremounted on the column for movement therealong between a lower positionnear the ballast chamber and an upper position adjacent the upper end ofthe column and means for securing the superstructure in its upperposition, the ballast chamber being floodable to convert the vessel froma transit condition in which the ballast chamber floats in the waterwith the superstructure in its lower position, to an intermediatecondition in which the ballast chamber is sunk in the water to draw thecolumn downwardly through the superstructure as it floats in the wateruntil the superstructure is at a position adjacent the upper end of thecolumn and is secured thereto by the securing means, and said chamberbeing partially unballastable to elevate the superstructure clear of thewater, wherein the improvement comprises a plurality of spaced mooringlines connected to the vessel at or near the lower end of the column andbeing arranged for attachment to anchorage points, a mooring linesupport associated with the superstructure and movable upwardlytherewith, and each mooring line extending from its point of connectionto the vessel over said support and to its anchorage point, wherebydisplacement of the lower end of the vessel and the superstructure awayfrom each other takes up slack in the lines and assists in tensioningthem.

2. A vessel as claimed in claim 1, wherein the support comprises a ringwhich encircles the column and is connected to the superstructure, saidring carrying, for each line, a rotatable support element over which theline passes.

3. A vessel as claimed in claim 2, wherein the rotatable supportelements are each disposed on a pin which is mounted in a bracketdepending from the ring.

4. A vessel as claimed in claim 1, wherein the ends of the mooring linesat the vessel are secured to attachment points at the base of thecolumn.

References Cited UNITED STATES PATENTS 3,031,997 5/1962 Nesbitt 1l40.53,294,051 12/1966 Khelstovsky 1l40.5

TRYGVE M. BLIX, Primary Examiner US. Cl. X.R.

